Conventionally, closed-caption broadcasting that causes closed captions to be displayed for users including people with hearing difficulties along with video and sound of a television program has been performed.
The closed-caption broadcasting is applied only in specific television programs that are organized by broadcasting stations. Thus, the users cannot be offered presentation of the closed captions in television programs not corresponding to the closed caption broadcasting.
Therefore, Patent Document 1 discloses a closed-caption superimposition device that displays video, to which closed captions are added based on video signals and sound signals. The closed caption superimposition device acquires the sound signals by receiving broadcasting signals while converting the sound signals into character codes by sound recognition. Then, the closed caption superimposition device produces the closed captions (character pattern data) from the converted character codes, and superimposes the produced closed captions on the video signals.
This allows the users to be offered presentation of the closed captions in all television programs whether or not those television programs correspond to the closed caption broadcasting.
[Patent Document 1] JP 5-176232 A